1. Field of the Invention
The present invention relates to a battery pack used, for example, in conjunction with a camcorder or other portable video camera device and, more particularly, to a rechargeable battery pack having a pin terminal providing improved durability and longevity to the battery pack.
2. Description of the Related Art
Battery packs used, for example, with portable electronic devices such as portable video cameras, have found increasing utility in recent years due to the burgeoning popularity and proliferation of diverse portable electronic devices and the need to provide power to such devices on an ongoing basis whenever and wherever the user wishes to employ them. Generally, such battery packs comprise an insulated housing, at least one rechargeable battery permanently encased in the housing, and a structural mechanism for attaching the battery pack to an electronic device in such a manner that electrical energy may be continuously supplied from the battery to the electronic device.
One such known and commercially available battery pack for a portable video camera is illustrated in FIGS. 1A and B. As shown in FIG. 1A, battery pack 10 comprises an insulated casing 11 and rechargeable batteries 12 and 13 connected in series and encased in side-by-side relation within casing 11. Open-ended anode and cathode pin terminals 14 and 15 are provided within opposed corner sections of casing 11 and have open outer ends extending to an end of the casing 11 and are open to receive connecting pins of an electronic device. A slot or groove may be provided on an outer surface of insulated casing 11 to guide the battery pack 10 into appropriate engagement with a portable video camera (not shown) during insertion. Pin terminals 14 and 15 comprise open-ended hollow metal cylindrical contact elements arranged in open-ended cylindrical holes formed in the molded plastic body of housing or casing 11. Metal contact elements within the terminals 14 and 15 maintain electrical contact with batteries 12 and 13.
In use, battery pack 10 is inserted into a battery chamber provided in a video camera (not shown). The battery chamber has substantially the same size and cross-sectional shape as the battery pack 10. Upon insertion of the battery pack into the battery chamber of the video camera, the slots or grooves in the battery housing are received by and slide along a complimentary ridge formed on an inner wall of the video camera chamber. At the inner end of the video camera chamber, terminals 14 and 15 of the battery pack engage and receive therein cylindrical metal pins arranged on an inner end wall of the chamber. Electrical energy is thus provided to the video camera from batteries 12 and 13, through the metal contact elements within terminals 14 and 15, and finally to and through the metal pins formed on the inner end wall of the hollow video camera chamber.
There are problems associated with this commercially available battery pack. Most importantly, the diameter of the cylindrical metal contact elements within the terminals is slightly larger than the diameter of the video camera pins that they receive, so that the pins may be successfully inserted into terminals 14 and 15. However, wear and tear on the video camera pins and metal contacts of the terminals, resulting from continued engagement and disengagement of the battery pack with the video camera, loosens the fit of the pins in terminals 14 and 15, resulting in deterioration of the desired electrical connection. Moreover, dirt and lint accumulate over time in the interior of terminals 14 and 15, adversely affecting the interconnection of the battery pack and the video camera and further deteriorating the desired electrical connection.
Another known and commercially available battery pack for a portable video camera is illustrated in FIGS. 2A and B. The battery pack of FIGS. 2A and B has a similar housing and battery arrangement as the battery pack shown in FIG. 1. Moreover, as shown in FIG. 2A, open-ended anode and cathode pin terminals 24 and 25 are formed at opposed corner sections of casing 21 and have open ends. However, terminals 24 and 25 are not formed as cylindrical holes within casing 21, but rather are formed as open-sided U-shaped terminals with open-sided U-shaped metal contact elements 27 and 28 arranged therein. The open sides of terminals 24 and 25 and metal contact elements 27 and 28 allow accumulated lint and dirt to be easily removed from the terminals. The separation between the U-shaped metal contact elements 27 and 28 is, at its closest, slightly smaller than the diameter of the pins of the video camera that it is adapted to engage. The upper and lower faces of the metal contact elements 27 and 28 are flexible and curved slightly inwardly to create an inward spring bias. Accordingly, as a video camera pin is inserted, for example, into terminal 24, the cylindrical surface of the pin pushes against the flexible biased upper and lower faces of metal contact element 27. The inward spring bias of the upper and lower faces against the cylindrical surface of the pin creates a snug fit between the pin and the terminal 24 into which it is inserted.
The FIG. 2 battery pack improves upon the deficiencies of the FIG. 1 battery pack by providing terminals that can easily be cleaned of debris and by providing a fit between terminal and pin that is less subject to wear and deterioration. However, the battery pack shown in FIG. 2 is itself problematic. Specifically, the open-ended and open-sided terminal configuration results in a battery pack having a fragile bottom wall 30 that is easily broken. Rechargeable battery packs are frequently mishandled during use, by either being accidentally banged or dropped. The terminal wall 30 of the battery pack illustrated in FIG. 2 is easily subject to breakage during such mishandling, destroying the utility of the battery pack.
Accordingly, the need currently exists for a battery pack for electronic devices, such as a rechargeable battery pack for a portable video camera device, which not only achieves its intended function of providing electrical energy to the electronic device, but which is also characterized by durability and longevity of reliable optimum performance.